• Korean Journal of Applied Biomechanics
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• v.21 no.5
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• pp.561-571
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• 2011

The purpose of this study was to perform the kinematic analyses of the women's pole vault skills in IAAF World Championships Daegu 2011. Subjects were the 1st through 8th place finishers in the pole vault. The kinematic analyses were divided into four phases: two dimensional run up analysis, and three dimensional analyses for the remaining plant, swing up, and extension phases. Run-up variables consisted of run up distance, number of steps, average step length, ratio of step length to height, average velocity at the final 5~10 m, approach position. Three variables were analyzed during plant: pole angle, center of gravity (COG) velocity, and COG takeoff angle. Swing up phase variables included: pole flection angle, COG velocity (horizontal, vertical, resultant), COG trajectory and bar approach angle of COG. Compared to the 2009 World Championships in Berlin, the average vault height increased, while run up velocity and approach position were almost unchanged. However, horizontal velocity during the last two steps of the final approach decreased noticeably compared to speeds from 1990. These results reflect the change in both technique and physical fitness in pole vaulters. During extension, the peak height of COG surpassed the clearance height by an average of 0.11m. These specific results can help coaches and athletes modify training and improve performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.318-318
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• 2010

In this paper, we studied generating characteristic of cymbal type piezoelectric transducer according to change of cymbal cap. The transducer is composed of circular piezoelectric ceramic and two elastic bodies which are shaped as cymbal. Two elastic bodies are attached to upper and bottom of the ceramic. Principle of the transducer is to generate expanded displacement because vertical stress is transformed into horizontal stress by slope angle of elastic bodies. The transducer also has advantage of high durability by the angle of elastic bodies. In this study, each parameter was chosen, and then generating characteristics were analyzed by FEM program. The parameters were slope angle of cymbal cap (theta), cap height (h) and cap inner diameter(d). The model that had generating characteristic Of high voltage was chosen by results of the analysis. Besides, maximum vertical displacements according to change of vertical stress were analyzed by structural analysis in order to find out relation between the maximum vertical stress which can prevent from ceramic damage and conditions of each cap.

• Korean Journal of Applied Biomechanics
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• v.14 no.1
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• pp.83-98
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• 2004

The purpose of this study was to determine the kinematic variables of the hurdling for a korea record holder (A) and a national hurdle representative (B). after the kinematic variables such the distance and the distance and height of C.G, the velocity and the angle were analyzed about the hurdling. The results were summarized as follows; 1. In terms of the distance and the height of C.G, subject A showed long in horizontal distance from C.G to the take-off phase, but showed short in the landing phase. Subject B showed short in horizontal distance from C.G to the take-off phase, and showed long in the landing phase. 2. In terms of the velocity of C.G, Subject A showed fast C.G velocity in horizontal direction to the braking phase, Subject A and B showed slower C.G velority in the landing phase, but Subject A showed height C.G velocity in vertical direction to the to the take-off, the landing, and propulsion phase 3. In terms of the angle of C.G and lean of C.G to front at the braking and the take-off phase. Subject A kept the less angle in the maximum trunk lean to front at the flight phase as comparison with Subject B. 4. In terms of the velocity of the knee and the ankle joint. Subject A showed fast in the resultant velocity of the left ankle joint the take-off phase, but showed slow in the left knee joint. Subject B showed fast in the resultant velocity of the left knee joint the take-off phase, but showed slow in the right knee and the right ankle joint.

• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.431-444
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• 1997

This research was carried out to compares the treatment effects of Horizontal and Vertical type activators in Angle's Class II div. 1 maloccusion patients with mandibular retrusion dand to find out whether different treatment effects or growth pattern were observed between sexes in each study groups. The results were as follows: 1. In Horizontal activator group, forward positioning of mandible and vertical increase in anteror face as examplified by increase of LAFH and AEM were observed when pre and post-treatment datas were evaluated. 2. Males samples in Horizontal activator group showed increase in mandiular length accmpanied by posterior positioning of maxilla, wheras female samples in Horizontal activator group showed increase in mandibular body length, labial inclination of mandibular incisors and increase in lower anterior facial height .3. In vertical activator group, increase in AFH, LAFH, PFH and LPFH were observed when pre and post treatment datas were evaluated. 4. Male samples in Vertical activator group showed increase in mandibular body length and anterior and posterior facial heights, whereas females samples of Vertical activator group showed mainly increase in anterior facial height. 5. When pre and post treatment datas of Horizontal and Vertical activator groups were compared, skeletal difference were mainly observed in pretreatment datas but dental difference were observed in post treatment datas ,indicating that two actiators differ only in their effects to dental variables. 6. Difference between sexes were noted after treatment although no difference were observed between sexs in each groups before treatmentt. This indicates that inherent growth effects in each sex exerts more influence 1km appliances used for treatment.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.6
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• pp.361-367
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• 2016

In this paper, we propose an improved single view metrology (SVM) algorithm to accurately measure the height of objects. In order to accurately measure the size of objects, vanishing points have to be correctly estimated. There are two methods to estimate vanishing points. First, the user has to choose some horizontal and vertical lines in real world. Then, the user finds the cross points of the lines. Second, the user can obtain the vanishing points by using software algorithm such as [6-9]. In the former method, the user has to choose the lines manually to obtain accurate vanishing points. On the other hand, the latter method uses software algorithm to automatically obtain vanishing points. In this paper, we apply image resizing and edge sharpening as a pre-processing to the algorithm in order to improve performance. The estimated vanishing points algorithm create four vanishing point candidates: two points are horizontal candidates and the other two points are vertical candidates. However, a common image has two horizontal vanishing points and one vertical vanishing point. Thus, we eliminate a vertical vanishing point candidate by analyzing the histogram of angle distribution of vanishing point candidates. Experimental results show that the proposed algorithm outperforms conventional methods, [6] and [7]. In addition, the algorithm obtains similar performance with manual method with less than 5% of the measurement error.

• Korean Journal of Applied Biomechanics
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• v.14 no.3
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• pp.135-147
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• 2004

This study was conducted to investigate the technical factors of Lu Yu Fu vault actually performed by three men gymnasts participated in artistic gymnastics competition of 2003 summer Universiade in Daegu through the DLT method of three dimensional cinematography. To analyze these vaults, the instant events of Lu Yu Fu were set in the board touchdown(BTD), the board takeoff(BTO), the horse touchdown(HTD), the horse takeoff(HTO), the peak height(PH), the mat touchdown(MTD) respectively and the phases of that vault were set in the board contact(BC), the preflight(PRF), the horse contact(HC), the postflight(POF), the grounding on mat(GM) respectively After calculating the performance times, the CG displacement velocity, the kinetic energy impulse reaction force moment arm torque at the horse, the released angle piked angle addressed angle, the angular momentum angular velocity of whole body in x axis, and the horizontal displacement between the feet and CG, the following conclusions were reached. To perform the better Lu Yu Fu vault, a gymnast must have the large horizontal velocity of whole body with fast run-up, decrease the duration time and the horizontal vertical displacement of whole body in PRF, have the enough time to judge the correct magnitude and direction of force to brake or push the horse so as to lengthen the HC duration time at any cost. Also it is desirable to increase the horizontal vertical displacement of whole body in POF if possible, maintain the adequate piked position to decrease the angular velocity of whole body in x axis, prepare the grounding on mat previously and delay the release of the hand from the body to keep the angular momentum.

• The korean journal of orthodontics
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• v.37 no.3 s.122
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• pp.192-203
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• 2007

Objective: The aim of this study was assessment of the relationship between airway space and facial morphology in Class III children with nasal obstruction. Methods: For this study, 100 Class III children (50 boys and 50 girls) were chosen. All subjects were refered to ENT, due to nasal obstruction. Airway space measurements and facial morphology measurements were measured on lateral cephalometric radiograph. Pearson correlation analysis was used to assess the relationship between airway space and facial morphology Results: Ramal height, SNA, SNB, PFH, FHR and facial plane angle were positively related to upper PAS, and sum of saddle angle, articular angle, and genial angle, SN-GoGn, Y-axis to SN and FMA negatively related to upper PAS. Genial angle, FMA were positively related to lower PAS, and articular angle, facial depth, PFH and FHR negatively related to lower PAS. PCBL, ramal height, Mn. body length, Mn. body length to ACBL, facial depth, facial length, PFH and AFH were positively related to tonsil size. Sum of saddle angle, articular angle, genial angle, facial length, AFH, FMA and LFH were positively related to tongue gap, and IMPA and overbite was negatively related to tongue gap. Upper PAS, related to size of adenoid tissue, was mainly related to posterior facial dimension following a vertical growth pattern of face and mandibular rotation. Lower PAS and tonsil size, related to anterior-posterior tongue base position, were significantly related to each other. Lower PAS was related to growth pattern of mandible, and tonsil size was related to size of mandible and horizontal growth pattern of face. Tongue gap was related to anterior facial dimension following a vertical growth pattern of face. Conclusion: Significant relationship exists between airway space and facial morphology.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.5
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• pp.311-319
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• 2012

Purpose: The aim of this study is to evaluate the vertical changes of the lip and perioral soft tissue, following orthognathic surgery in skeletal class III patients by a cephalometric analysis of a cone beam computed tomography (CBCT). Methods: A total of 20 skeletal class III patients, who had bimaxillary surgery with Le Fort 1 osteotomy and bilateral sagittal split ramus osteotomy, were included in this study. The surgical plan for maxilla was posterosuperior impaction with the anterior nasal spine, as the rotation center. Further, the surgical plan for mandible was also posterosuperior movement. The soft tissue changes between lateral cephalogram and CBCT were compared. And the correlations between independent variables and dependent variables were evaluated. Results: There were no significant differences of the soft tissues changes between lateral cephalogram and CBCT. Upper lip philtrum length (SnLs), nasolabial angle increased and upper lip vermilion length (LsStms), lower lip length (StmiB'), lower lip vermilion length (StmiLi), lower lip philtrum length (LiB') and soft tissue lower facial height (SnMe') decreased after surgery. Change of SnLs (${\Delta}$SnLs) was influenced by vertical change of menton (${\Delta}$MeV), and change of LsStms (${\Delta}$LsStms) was influenced by upper lip thickness (ULT). Change of StmiLi' (${\Delta}$StmiLi') were influenced by preoperative overjet. Change of StmiB' (${\Delta}$StmiB') were influenced by preoperative overjet, vertical change of lower incisor (${\Delta}$L1V) and horizontal change of posterior nasal spine (${\Delta}$PNSH). Change of LiB' (${\Delta}$LiB') was influenced by ${\Delta}$L1V and ${\Delta}$PNSH. Change of SnMe' (${\Delta}$SnMe') was influenced by ${\Delta}$MeV, horizontal change of upper incisor (${\Delta}$U1H) and horizontal change of lower incisor (${\Delta}$L1H). ${\Delta}$Nasolabial angle was influenced by change of ULT (${\Delta}$ULT). Conclusion: Both soft tissues and hard tissues can be evaluated by CBCT. Posterosuperior rotation of maxillomandibular complex resulted in increase of upper lip philtrum length and nasolabial angle, while the upper lip vermilion length, lower lip philtrum length, lower lip vermilion length, and soft tissue lower facial height showed a decrease.

• Journal of the Korean Geotechnical Society
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• v.33 no.11
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• pp.59-72
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• 2017

In this study, the calculation method of the active earth pressure acting on the imaginary vertical plane at the end of the heel of the wall is proposed. For cantilever retaining wall, a change of shear zone behind the wall affects the earth pressure in the vertical plane at the end of heel of the wall depending on wall friction and angle of ground slope. It is very complicated to calculate the earth pressure by a limit equilibrium method (LEM) which considers angles of failure planes varying according to the heel length of the wall. So, the limit analysis method (LAM) is used for calculation of earth pressure in this study. Using the LAM, the earth pressures considering the actual slope angles of failure plane are calculated accurately, and then horizontal and vertical earth pressures are obtained from them respectively. This study results show that by decreasing the relative length of the heel, the slope angle of inward failure plane becomes larger than theoretical slope angle but the slope angle of outward failure plane does not change. And also the friction angle on the vertical plane at the end of the heel of the wall is between the ground slope angle and the wall friction angle, thereafter the active earth pressure decreases. Finally, the Coulomb earth pressure can be easily calculated from the relationship between friction angle (the ratio of vertical earth pressure to horizontal earth pressure) and relative length of the heel (the ratio of heel length to wall height).

• Journal of Electrical Engineering and Technology
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• v.5 no.2
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• pp.337-341
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• 2010

In this paper, an extremely low voltage operated micro corner cube retroreflector (CCR) was fabricated for free-space optical communication applications by using bulk silicon micromachining technologies. The CCR was comprised of an orthogonal vertical mirror and a horizontal actuated mirror. For low voltage operation, the horizontal actuated mirror was designed with two PZT cantilever actuators, torsional bars, hinges, and a mirror plate with a size of $400{\mu}m{\times}400{\mu}m$. In particular, the torsional bars and hinges were carefully simulated and designed to secure the flatness of the mirror plate by using a finite element method (FEM) simulator. The measured tilting angle was approximately $2^{\circ}$ at the applied voltage of 5 V. An orthogonal vertical mirror with an extremely smooth surface texture was fabricated using KOH wet etching and a double-SOI (silicon-on-insulator) wafer with a (110) silicon wafer. The fabricated orthogonal vertical mirror was comprised of four pairs of two mutually orthogonal flat mirrors with $400{\mu}m4 (length) $\times400{\mu}m$ (height) $\times30{\mu}m$ (thickness). The cross angles and surface roughness of the orthogonal vertical mirror were orthogonal, almost $90^{\circ}$ and 3.523 nm rms, respectively. The proposed CCR was completed by combining the orthogonal vertical and horizontal actuated mirrors. Data transmission and modulation at a frequency of 10 Hz was successfully demonstrated using the fabricated CCR at a distance of approximately 50 cm.